Background: The influenza B virus has two lineages; Yamagata and Victoria. The two lineages are antigenically distinct and it is difficult to expect cross-protection between the lineages. Actually, the mismatch between circulating influenza B viruses and vaccine strains has been occurred frequently. The cell-culture system for the production of influenza vaccine can contribute to improve vaccine stain selection and expand vaccine supplies. We investigated the immunogenicity and safety of cell culture-derived quadrivalent inactivated influenza vaccine (NBP607-QIV) in adults and elderly subjects.

Results: 1,503 participants were randomly assigned to NBP607-QIV (n=752), NBP607-Y (n=373) and NBP607-V (n=378). The seroconversion rates of NBP607-QIV were 52.4%, 51.2%, 43.7% and 55.8% against A/H1N1, A/H3N2, B/Yamagata and B/Victoria, respectively. Non-inferiority against shared strains and superiority against alternate-lineage B strains were demonstrated for NBP607-QIV vs. NBP607-Y and NBP607-V. AEs were reported from 48.5% of NBP607-QIV group. Majority of AEs was solicited and mild in intensity. In adults (aged 19-59 years), solicited local AEs were slightly more frequent in NBP607-QIV group than NBP607-Y or NBP607-V group (40.9%, 33.4% and 32.5%, respectively). One SAE was observed among NBP607-QIV group, which was considered to be unrelated to the study vaccine.

Conclusion: NBP607-QIV is a safe, well-tolerated and immunogenic influenza vaccine for Korean adults and elderly subjects.